Pt single atoms coupled with Ru nanoclusters enable robust hydrogen oxidation for high-performance anion exchange membrane fuel cells

The sluggish reaction kinetics of alkaline hydrogen oxidation reaction (HOR) is one of the key challenges for anion exchange membrane fuel cells (AEMFCs). To achieve robust alkaline HOR with minimized cost, we developed a single atom-cluster multiscale structure with isolated Pt single atoms anchored on Ru nanoclusters supported on nitrogen-doped carbon nanosheets (Pt1-Ru/NC). The well-defined structure not only provides multiple sites with varied affinity with the intermediates but also enables simultaneous modulation of different sites via interfacial interaction. In addition to weakening Ru–H bond strength, the isolated Pt sites are heavily involved in hydrogen adsorption and synergistically accelerate the Volmer step with the help of Ru sites. Furthermore, this catalyst configuration inhibits the excessive occupancy of oxygen-containing species on Ru sites and facilitates the HOR at elevated potentials. The Pt1-Ru/NC catalyst exhibits superior alkaline HOR performance with extremely high activity and excellent CO-tolerance. An AEMFC with a 0.1 mg·cm_PGM⁻² loading of Pt1-Ru/NC anode catalyst achieves a peak powder density of 1172 mW·cm⁻², which is 2.17 and 1.55 times higher than that of Pt/C and PtRu/C, respectively. This work provides a new catalyst concept to address the sluggish kinetics of electrocatalytic reactions containing multiple intermediates and elemental steps.